1. Field of the Invention
This invention is related to a proportional control gas valve that is capable of linearly controlling a relatively large range of gas flow while utilizing a very small amount of energy. Furthermore, it has a fail-safe mode of operation.
2. Description of the Prior Art
One of the conventional ways to control the flow rate of gas fuel is accomplished by having a number of gas buners present within a heating apparatus. When little heat is required, only some of those gas burners will operate. As more heat is required, more gas burners will operate with the apparatus. Another conventional way to control the flow rate of gas fuel within a heating apparatus is to use several solenoid gas valves within a burner to control the flow rate of gas fuel. As more heat is needed, more of the valves within a burner commence operation within the heating apparatus.
However, while the result of having many gas burners operate simultaneously is an increase in heat output, the operation of many burners also results in increased cost, and makes it impossible to control gas flow linearly. Likewise, having a number of solenoid gas valves operate within a burner increases the costs of heating as more gas valves are required, and also cannot regulate gas flow linearly.
The costs of operating a conventional heating apparatus through the use of gas burners have generally been high because each of the burners require a gas solenoid valve for operation control. The conventional gas solenoid valve must be controlled manually, through the use of a switch or the like to control gas flow. However, by this method, gas flow cannot be controlled linearly.
Because the conventional gas solenoid valve is mable to control a large range of gas fuel flow rate, the typical heating apparatus, using the conventional gas solenoid valve, has a choice of flow rate from between one (1) to five (5) minimum heat to m heat range settings. This is a limited range of heat settings, reflecting the inability of the conventional gas solenoid valve to regulate a large range of gas fuel flow.
The small range of gas fuel flow provided by the gas solenoid valve has a number of disadvantages. One disadvantage is that the gas solenoid valve cannot meet the needs of heat users requiring heat at a precise temperature. Another disadvantage is that the small gas fuel flow range can waste energy, as heat users may be forced to utilize a higher heat setting than required because of the limited range of heat settings provided through the use of the conventional gas solenoid valve.
Furthermore, the conventional gas solenoid valve is very complicated in structure and requires a considerable amount of energy for operation. The conventional gas solenoid valve generally includes a magnetic circuit formed with a fixed iron core, magnets and a magnetic member. A coil holder is movably provided with respect to the outer periphery of the fixed iron core and has a magnetic coil wound around itself A sleeve is accommodated within the magnets and ed apart from the outer periphery of the fixed iron core for a determined distance. An actuating portion is formed with the fixed iron core. Therefore, it can be seen that the conventional gas solenoid valve is complex in structure.
Furthermore, should the fire igniting the gas fuel within a heating apparatus stop of its own accord, without being manually turned off, the conventional gas solenoid valve is not equipped to halt the gas fuel flow. Thus the gas fuel will flow at the rate set by the manual switch heat range setting, until the heating apparatus is manually switched off This is a potentially very dangerous situation.
Thus, it is an object of the present invention to provide an improved proportional control gas valve which can obviate and initiate the above-mentioned drawbacks.